Hierarchy of prediction errors for auditory events in human temporal and frontal cortex

TLDR

Organisms must constantly predict future events based on past regularities, and when predictions are violated action may be required; these regularities span subsecond repetitions to complex long‑timescale structures. The study seeks to determine how distinct brain regions monitor temporal regularities and generate prediction error signals. The authors recorded subdural electrocorticography while presenting auditory stimuli with local and global regularities, finding that frontal cortex responds with high‑frequency activity only to globally unpredictable changes, whereas temporal cortex responds to any immediate change. The findings demonstrate a hierarchical predictive coding system, with frontal cortex encoding global prediction errors and temporal cortex encoding local prediction errors, as directly recorded from the human brain.

Abstract

Significance To survive, organisms must constantly form predictions of the future based on past regularities. When predictions are violated, action may be needed. Different scales of environmental regularity need to encompass both subsecond repetitions and complex structures spanning longer timescales. How different parts of the brain monitor these temporal regularities and produce prediction error signals is unclear. Utilizing subdural electrocorticographic electrodes with an auditory paradigm involving local and global regularities, we show that frontal cortex is sensitive to the big picture, responding with high γ-band activity exclusively to globally unpredictable changes, whereas the temporal cortex equally responds to any change in the immediate history. These results reveal a hierarchy of predictive coding recorded directly from the human brain.